Abstract
In the root meristem (RM), stem cells surround niche cells, the quiescent center. Stem cells maintain their stemness within their niche and commence stereotyped cell division sequences. Until recently, little is known about the molecular mechanisms underlying the stem cell maintenance in RM. Previous experiments have shown that laser-ablated stem cells could be compensated for by adjacent cells. This cell invasion process often results in abnormal root cell patterns. These observations suggest that mutants defective in the root stem cell maintenance likely exhibit abnormal root cell patterning rather than retardation of root growth.
Based on this working hypothesis, we isolated several Arabidopsis mutants defective in root cell patterns. One of the mutant contained reduced number of cells in the root vascular tissue, and its causal gene was found to encode a novel protein containing WD40-motifs. We will report detailed characterization of the mutants and discuss functions of their causal genes.
